U.S. Geothermal Announces Mechanical Completion of New San Emidio Power Plant

BOISE, IDAHO--(Marketwire - Dec. 20, 2011) - U.S. Geothermal Inc. (TSX:GTH)(NYSE Amex:HTM), a leading renewable energy company focused on the development, production and sale of electricity from geothermal energy, announced that it has been informed by engineering, procurement, and construction contractor, SAIC Constructors LLC, that mechanical completion has been achieved on a new power plant at Phase I of its San Emidio project, located in Washoe County, Nevada. The new 8.6 net megawatt, water cooled plant is replacing an existing operating power plant that will be shut down as part of the new plant startup.

Mechanical completion starts commissioning activities on various individual power plant components and controls. Once the commissioning activities are complete, the full power plant will undergo acceptance testing, leading to startup and commercial operation. The Phase I power plant is expected to achieve commercial operations in approximately 30 days.

The Phase II power plant development at San Emidio has commenced construction with initiation of production and injection well drilling at the site. Recent drilling has identified a deeper, higher temperature potential production zone in the south area of the existing reservoir, which is expected to expand the known reservoir boundary. Phase II is a planned 8.6 net megawatt, air cooled power plant and is scheduled to be on line during the 3^rd quarter of 2013.

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About U.S. Geothermal Inc.:

U.S. Geothermal Inc. is a leading renewable energy development company that is operating geothermal power projects at Raft River, Idaho and San Emidio, Nevada. The Neal Hot Springs project, which is currently under construction, will be the company's third operating power project. The company holds geothermal energy rights to 69,500 acres comprising six advanced stage geothermal development projects. The San Emidio project is currently undergoing construction of a new 8.6 net MW binary cycle power plant.

The information provided in this news release may contain forward-looking statements within the definition of the Safe Harbor provisions of the US Private Securities Litigation Reform Act of 1995. These statements are based on U.S. Geothermal Inc.'s current expectations and beliefs and are subject to a number of risks and uncertainties that can cause actual results to differ materially from those described, including but not limited to, the results from the exploration, production and injection well drilling at San Emidio. Readers are cautioned to review the risk factors identified by the company in its filings with Canadian and US securities agencies. Forward-looking statements are based on management's expectations, beliefs and opinions on the date the statements are made. U.S. Geothermal Inc. assumes no obligation to update forward-looking statements if management's expectations, beliefs, or opinions, or other factors, should change.